Metric Bolt Assortment M2 M3 M4, 21 Sizes 4MM to 30MM Upgraded Zinc Plated Hex Socket Head Cap Machine Screws, 12.9 Alloy Steel Bolts and Nuts Kit Screws Nuts and Washers

It appears the factory that this product comes from does not oil—specifically—the nuts and washers on the black oxide sets. All of the bolts themselves came coated in oil. Even without the oil, none of the nuts, washers, or bolts themselves were rusty on arrival. That "rusty" appearance coating the inside of the nut & washers bag is just loose dirt & oxide powder from the giant bin at the dirty mill/factory that makes its way into the bag along with the fasteners when they fill them. I just dumped the 6 nut and washer bags into disposable cups, sprayed some WD-40 on them, and then wiped the excess away with a paper towel. You'll see after cleaning the dust off that they have no actual rust on them. They're in good condition and work well. Kind of a pain since they're new, but it only took a few minutes. Black oxide is supposed to have oil applied to it, so you should oil the nuts and washers if you choose either of the black oxide sets. I also recommend reserving the black oxide sets for indoor & dry conditions, as they won't hold up well to wet conditions for very long without rusting (even with oil applied). Grab the stainless set if you plan to use them in outdoor or wet conditions. Overall, this is a great set of fasteners.

I bought these to use with a set of metric screw inserts. They match up very well. I also used them in several other projects where I had to use a nut and that also worked well. I like the selection of sizes and the quantity is sufficient. I especially like that washers and nuts are included so that I do not have to purchase them separately.

If you are adding to your hardware selection(collection), then this is a great buy. The screws, nuts, and washers come in a divider, but in individual zip lock baggies. So it'll take a bit of time to get them all opened up and put into the divider. One thing to note is that there are more types of items than there are spaces for them in the divider. I just kept 3 items in their original zip lock bags until I can get the correct storage divider for them. Also, I was missing the M3x25 bolts, but had an additional bag of M3 nuts. I won't remove any stars because of this, because you can see what a simple mistake that would be to make. I'm sure these are hand packed assembly line style. And it's not a big deal.

Used for small 3D printing project assembly. Well organized. Cheap case but you get what you pay for. It does the job.

Really like this hardware kit. The hardware comes in individual bags and I had to fight the temptation to open all of the little ziploc bags and dump them out. The hardware being bagged is actually a great feature and makes a lot of sense as soon as you knock the tray off the table and it dumps on the ground. Took 20 seconds to pick it all up as opposed to 20 minutes and then 2 hours measuring with dial calipers:)